Method of forming ribbed metal pipes.



A. M. STEWART. METHOD OF FORMING RIBBBD METAL PIPES APPLICATION FILED MAR.24,191&

L1$3fi1 6., Patented Jan.5,1915.

ATTORNEYS body of the pipe,

lindrical form t substantial, ow'of metal to ash ape rei'axis to substantially cylindrical pipe into a pipe with'a shape or cross-section resembling an 'elli'pseor oval, and simultaneously or afteriward press together the longitudinal portions of the more or less elliptical or oval pipe at form longitudinal ribs on the pipe. "Preferably at the same time I change the that is the pipe irrespective of the ribs, back to a substantially cyby making the longer and shorter axes ofthe said shape e uali However, this step may be omitted it a cylindrh cal ribbed pipe is not desired asa finished article.

I claim 7-1. The method of changing a substantially cylindrical pipe of substantially uniform wall-thickness into a longitudinally ribbed pipe having substantially the same Wall thickness, which "consists in changing the crosssectionofthe pi eby bending action Withopposite sides of the major or longer senibling an ellipse, and pressing together the proximate portions thereof at opposite l sides of the ends of the major axis of the said shape to form longitudinal ribs.

2. The method of changing a substantially cylindrical pipe of substantially uniform Wall-thickness into a longitudinally ribbed 1 Ohio, this 18th day of A. M. STEWART. Witnesses:

G. W. Sunni-1n, C. H. AUFDERHEIDE. 

